Infectious disease specialist is a health care provider who deals with the diagnosis and management of infectious diseases. Infectious diseases can be caused by virus, bacteria, fungi or parasites. Common infectious diseases are actinomycosis, trypanosomiasis, AIDS, anthrax, bacterial pneumonia, botulism, cellulitis, cholera, common cold, diphtheria, gas gangrene, hepatitis, gonorrhea, syphilis, meningitis and encephalitis.